Digital electronic devices such as mobile computers and cellular phones are now becoming increasingly common. Digital terrestrial broadcasting will start in the near future in Japan. Examples of digital electronic devices for digital terrestrial broadcasting include liquid crystal displays and plasma displays. These digital electronic devices include a large number of LSIs.
For this reason, power source circuits of these digital electronic devices such as liquid crystal displays and plasma displays include a large number of capacitors for bypassing. When such capacitors require high capacitance, multilayer ceramic capacitors having a high relative dielectric constant (for example, see Patent Document 1) are employed. In contrast, when a temperature characteristic is more important than capacitance in such capacitors, temperature-compensating multilayer ceramic capacitors having low capacitance variation (for example, see Patent Document 2) are employed.
However, since the multilayer ceramic capacitor with a high relative dielectric constant disclosed in Patent Document 1 is constituted by crystal grains of a dielectric ceramic having ferroelectricity, such a ceramic capacitor has large temperature dependent variation of the relative dielectric constant and has large hysteresis exhibiting dielectric polarization, which has been a problem.
When a capacitor including such a dielectric ceramic having ferroelectricity is used in a power source circuit, noise caused by electrical induction distortion tends to be emitted. This hampers use of such a capacitor for plasma displays and the like.
On the other hand, temperature-compensating multilayer ceramic capacitors include dielectric ceramics mainly exhibiting paraelectricity, and hence these ceramic capacitors have low spontaneous polarization. For this reason, these ceramic capacitors have an advantage that electrical distortion typical of ferroelectricity does not occur. However, the dielectric ceramics of such ceramic capacitors have a low relative dielectric constant and hence such ceramic capacitors do not provide sufficient performance as by-pass capacitors, which has been a problem.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2001-89231
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2001-294481